1. Field of the Invention
The present invention is directed to a support-request processing system using GPS data for locating a person requesting a support, and more particularly to such a system using a decentralized Global Positioning System (GPS) to locate a person requesting the support.
2. Description of the Prior Art
A decentralized GPS system such as disclosed in U.S. Pat. Nos. 5,119,102 and 5,379,224 has been proposed to reduce search of a person requesting an urgent support for rescue. The system utilizes a GPS terminal to be carried by a person, and a message center which is linked through a radio communication network to the GPS terminal and acts in response to a support-request signal from the person to give a warning message including a position of the person for prompting a suitable support. The GPS terminal is capable of receiving GPS data from GPS satellites and of transmitting the support request signal together with the GPS data to the message center. The GPS data is processed at the message center rather than at the GPS terminal for calculating a position of the GPS terminal so as to eliminate a calculation circuitry from the GPS terminal and to make the GPS terminal compact sufficiently to be portable. Thus decentralized GPS system, however, is still insufficient in that when the person is in a dead-area such as a building where the GPS data from the GPS satellites is not available but the radio communication with the message center is available, the support-request signal can not be accompanied with a true GPS data so that the message center fails to locate the position of the person, making it difficult to rescue the person.
In view of the above insufficiency that the prior GPS system may have in locating the person requesting the support, and also in view of that the person is generally expected to move by vehicle and walk a short distance from the vehicle into buildings or the like area obstructing the GPS satellites, the present invention has been achieved to provide a system which is supplemented with a mobile terminal to be carried by the person separately from a GPS terminal left in the vehicle and receiving the GPS data, thereby enabling to estimate the location of the person around the GPS terminal or the vehicle even when the person is within buildings or a like area where the GPS data from the GPS satellites is not available, which is therefore a primary object of the present invention.
The system in accordance with the present invention includes a GPS terminal capable of receiving the GPS data from GPS satellites and transmits the GPS data to a radio communication network, and a message center which receives the GPS data from the GPS terminal through the radio communication network for processing the GPS data to calculate a position of the GPS terminal. The system additionally includes a mobile terminal provided separately from the GPS terminal to be carried by a person. The mobile terminal is capable of radio communication with the GPS terminal and is provided with a request key which issues a support-request signal upon being activated. The GPS terminal has a transmit means which, in response to the support-request signal, transmits the GPS data to the message center. At least one of the GPS terminal and the mobile terminal has an identification (ID) code which is transmitted through the radio communication network to the message center as a result of that the support-request signal is transmitted to the message center. The message center has a database table which stores a relation between the ID code and personal information about the person so that the message center can relate the position of the GPS terminal to the person giving the support-request signal. Further, the message center has an alarm means which notifies a support-request message including the personal information and the related position of the GPS terminal for prompting a suitable support action for the person requesting the support. Accordingly, even when the person is within the buildings or the like environment where the GPS satellites cannot be reached, the GPS data can be received by the GPS terminal which is located in a nearby position of acquiring the GPS data so that the message center can estimate the location of the person from the detected position of the GPS terminal.
Preferably, the mobile terminal transmits the support-request signal over the radio communication network so that the GPS terminal can be designed to use the radio communication network commonly for communication with the mobile terminal as well as the message center.
In one version of the present invention, the message center has a GPS calling device which, in response to the support-request signal, issues a GPS call signal to the GPS terminal through the radio communication network. The GPS terminal is activated by the GPS call signal to receive the GPS data from the GPS satellites and transmit the GPS data to the message center. Thus, the message center can firstly acknowledge the support-request signal and take over a subsequent procedure of locating the person under a supervision of the message center.
In this connection, the mobile terminal is provided with an ID data transmitting means for transmitting to the message center an identification (ID) data assigned to the mobile terminal The GPS calling device has a discriminating means which verifies the ID data and issues the GPS call signal only when the ID data from the mobile terminal matches one of registered ID data stored in the message center. Thus, the message center can proceed the locating operation only for the verified person, thereby eliminating erroneous locating operation.
Alternatively, in order to avoid the unnecessary locating operation, the message center may be provided with a registration means for registration of a call number assigned to the mobile terminal, and also with a call number verifying means which verifies the call number and causes the GS calling device to issue the GPS call signal only when the call number is registered in the registration means.
The mobile terminal is preferred to have an input means for entering a positional difference data indicating a positional difference between the mobile terminal carried by the person and the GPS terminal attached to, for example, the vehicle. The positional difference data is transmitted to the GPS terminal together with the support-request signal so that the GPS terminal responds to transmit the GPS data together with the positional difference data to the message center, thereby enabling the message center to estimate a location of the person around the GPS terminal in consideration of the positional difference. Thus, the actual position of the person around the GPS terminal can be successfully estimated.
In order to also give a reliable estimation of the person around the GPS terminal, the mobile terminal may be provided with a pedometer which counts the number of footsteps in walking by a person carrying the mobile terminal away from the GPS terminal to obtain a distance between the mobile terminal and the GPS terminal. Thus obtained distance is transmitted along with the support-request signal to the GPS terminal which in turn transmits the distance in addition to the GPS data to the message center in response to the support-request signal so that the message center can estimate a location of the person around the GPS terminal.
Further, the mobile terminal may include a direction detector in addition to a pedometer counting the number of footsteps of the person in walking away from the GPS terminal. The direction detector is provided to detect a direction in which the person walks away from the GPS terminal. The mobile terminal also includes an estimating means for analyzing the number of the footsteps and the direction to give an estimated distance between the GPS terminal and the mobile terminal. The estimated distance is then transmitted together with the support-request signal to the GPS terminal which is in turn made active to transmit the GPS data as well as the estimated distance to the message center so that the message center can estimate a location of the person around the GPS terminal.
Instead, the GPS terminal may be equipped with a direction entry means for entering a direction in which the person carrying the mobile terminal intends to move away from the GPS terminal. Thus entered direction is transmitted together with the GPS data to the message center so that the message center can estimate a location of the person around the GPS terminal, taking the distance into consideration.
In another version, the system is contemplated to give a warning when the person has not returned to the GPS terminal within a predetermined time period. For this purpose, the GPS terminal is designed to include a timer counting a time, a set-and-reset means, and a return-check means. The set-and-reset means is provided for setting a scheduled absent time period during which the person intends to be kept away from the GPS terminal and activating the timer to start counting the time, and for resetting the timer to stop counting, respectively. The return-check means judges whether or not the time is reset within the scheduled absent time period and issues a warning signal when the timer is not reset within the scheduled absent time period. Upon occurrence of the warning signal, the GPS terminal transmits the GPS data together with the warning signal to the message center so that the message center responds to give a warning message indicative of that the person has not returned to the GPS terminal within the scheduled absent time period and to calculate the position of the GPS terminal. Thus, the message center can give the warning that the person may be certainly involved in a trouble, thereby enabling an immediate support or rescue by the help of the known position of the GPS terminal.
In this connection, the return-check means may be designed to issue a confirmation signal rather than issuing the warning signal when the timer is not reset within the scheduled absent time period. Also, the mobile terminal includes an extension means capable of issuing an extension-request signal in reply to the confirmation signal. In the presence of the extension-request signal, the GPS terminal acts to extend the scheduled absent time period and otherwise acts to provide an absent warning and to transmit the GPS data together with the absent warning to the message center, whereby the message center can give a warning message indicative of that the person has not returned to the GPS terminal within the scheduled absent time and calculate the position of the GPS terminal for immediate support or rescue of the person. In this version, the system can afford flexible in matching with an individual behavior of the person for reliable supervision of the person.
In the meanwhile, the mobile terminal may be designed to have a capability of communicating with the GPS terminal by way of a minute power radio communication for transmitting the support-request signal to the GPS terminal, thereby simplifying the circuit configuration of the mobile terminal and reducing the manufacturing cost thereof.
In this instance, the mobile terminal is preferred to have a communication check means and a display. The communication check means checks regularly whether the mobile terminal is within an effective range for communication with the GPS terminal and provides a disable signal when the mobile terminal goes out of the effective range. Upon seeing the disable signal, the mobile terminal gives an out-of-range message on the display, prompting the person to move back into the effective range if the support-request is impending.
For the system where the mobile terminal communicates with the GPS terminal by use of the minute power radio communication, the GPS terminal may include an antenna with varying directivity for radio communication with the mobile terminal, and a direction detector which detects a direction in which the antenna shows the strong directivity. The GPS terminal acts, in response to the support-request signal, to transmit the GPS data as well as the detected direction to the message center so that the message center can estimate a location of the person around the GPS terminal with the help of the direction.
Further, instead of or in addition to the direction detector, the GPS terminal may include a recording mean which records a received field strength varying with time for the radio communication with the mobile terminal. The GPS terminal, in response to the support-request signal, transmits the latest data of the received field strength along with the GPS data to the message center. The message center has a means which analyzes the received field strength data to estimate a location of the person around the GPS terminal.
Still further, the GPS terminal may include a time counter which counts a time while the mobile terminal is out of range for communication with the GPS terminal, and a check means which issues a time warning signal when the counted time exceeds a predetermined level. The time warning signal is then transmitted together with the GPS data to the message center so that the message center can acknowledge and indicate that the person carrying the mobile terminal has not returned into the range capable for communication with the GPS terminal within a predetermined time. Thus, the message center can notify that the person is possibly involved in a trouble and take a suitable support for the person based upon the detected position of the GPS terminal.
In a further version of the present invention, the system includes a charger adapted to be coupled to the GPS terminal for charging a rechargeable battery incorporated in the GPS terminal. The charger has a radio communication means for receiving the support-request signal from the mobile terminal by way of a minute power radio communication. The GPS terminal is designed to have an inlet which is in direct connection with an outlet of the charger to take the support-request signal received at the radio communication means. Thus, even when the GPS terminal is brought back to the person""s home or the like premises for charging the battery, the GPS terminal can successfully responds to the support-request signal from the mobile terminal simply by disposing the GPS terminal together with the charger near a window or the like location where the GPS satellites can be viewed.
Alternatively, the system may include an intermediate receiver in combination with the charger for extending a distance of radio communication between the mobile terminal and the GPS terminal within the premises. The intermediate receiver is provided to receive the support-request from the mobile terminal, while the charger is adapted to be coupled to an AC power line to obtain therefrom a charging current. The intermediate receiver is adapted to be coupled also to the AC power line and has a superimpose means by which the support-request signal is superimposed upon an AC source voltage supplied through the AC power line. The charger has a signal extract means which extracts the support-request signal from the AC source voltage and feeds the same to the GPS terminal through a direct coupling therebetween. Thus, the mobile terminal can successfully transmit the support-request signal to the GPS terminal by way of the intermediate receiver over an extended distance within the premises while the GPS terminal is being charged.
These and still other objects and advantageous features of the present invention will become more apparent from the following description of the embodiments when taken in conjunction with the attached drawings.